What MP4 Videos Work As Video Texture On iPhone

Hi, I tried to create a video texture using THREE.VideoTexture(), but it only rendered black on the iPhone. Since the Three.js video texture example works fine on iPhone, I replaced my video source with the one from Three.js, and then it worked. Both were MP4 files, anyone has an idea what the criteria would be for MP4 files to work with video textures on the iPhone (iOS 15.4 in my case, but would be nice if it works on older versions as well)? My video file didn’t cause any troubles when embedded in the HTML directly.